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Thursday, 20 April 2017

Sea creatures 'dissolving' in acidifying ocean

The
mixture of warming waters and ocean acidification is proving a lethal
combination for many sea creatures who are dissolving in the hostile
conditions, according to a new study.

The study,
from the University of California, found that marine animals are
dissolving in Pacific waters off the Northern California coast.

“We
thought there would be some thinning or reduced mass,” said lead
author Dan Swezey of the study, which saw ocean conditions recreated
in a lab with cloned tiny invertebrates, known as bryozoans. “But
whole features just dissolved practically before our eyes.”

The
bryozoans were exposed to various combinations of dissolved carbon
dioxide, warmer temperatures and food concentrations – with large
numbers of their skeletons disappearing in as few as two months.

The
scientists also found that bryozoans, when consuming less food, began
building higher levels of magnesium into their skeletons, which made
them especially susceptible to ocean acidification.

During
the experiment researchers learned that bryozoans, which grow in
connected colonies, attempted to survive by shutting down parts of
themselves which were experiencing ocean acidification, redirecting
their energy to new growth. However, the creatures could not outpace
the dissolution.

“They
were trying to grow but were dissolving at the same time,”
said Swezey.

The
findings are cause for “growing
concern as oceans continue to warm and acidify,”
according the paper’s researchers, especially for calcified marine
animals.

"Marine
life is increasingly faced with many changes at once," saidco-author
Sanford, a professor in the UC Davis Department of Evolution and
Ecology.

"For
bryozoans, their response to warmer temperature makes them
unexpectedly vulnerable to ocean acidification. The question now is
whether other marine species might respond in a similar way."

The
study’s findings were published in the Proceedings of the Royal
Society B: Biological Sciences journal.